Rotary drilling bit



Feb. 27, 1934. 5 R HOPKlNs Y I 1,949,049

ROTARY DRILLING BIT Filed Oct. 29; 1929 2 Sheets-Sheet l 4 Feb. 27, 1934. l s Rb lHQPKlNS 1,949,049

ROTARY DRILLING BIT Filed Oct. 29, 19729 2 Sheets-Sheet 2 between the cutters and the mounting studs for the cutters, leaving the body unimpaired.

It is another object of the present invention to provide a bit of the character mentioned in whichthe several cutters projecting downwardly from the body are entirely free to rotate independently. By the present invention the cutters operate independent of each other so that the cutting action of the bit is not totally impaired even though one of the'cutters may, for some reason or other, be fouled or stuck so that it does not operate to the best advantage.

A further object of the invention is to provide a bit of the character mentioned in which the rotatable cutters present horizontal cutting edges to engage the bottom of the well bore and in which the cutters are related to the body so that the horizontal cutting edges act' on the formation at various angles during the operation of the bit.

Another object of the present invention lis to provide bit of the character mentioned which has an underreaming laction, that is.. an action which operates to make a bore somewhat larger in diameter than that required to pass the bit.

It is a further object of the invention to provide a bit of the character described having rotatable cutters with teeth the lower ends of which are horizontally disposed to lact on the bottom of a well boreand the outer ends or edges of which are vertically disposed to act on the wall of the bore.

It is another object of the'invention to provide a simple, practical, effective construction of the type above referred to in which the rotatable cutters rotate on their individual axes in a direction opposite to their bodily rotation about the axis of the tool.

There are other objects and features of the invention which, together with those above referred to, will be best and more fully understood from the following detailed description of typical forms and applications of the invention, throughout which description I refer to the accompanying drawings, in which:

Fig. 1 is a side elevation of a typical and simple form of bit embodying the invention, being a view of a bit employing two rotatable cutters. Fig. 2 is an enlarged detailed sectional view takenat the lower portion of the bit showing in detail the' mounting of acutter and the provision made for circulating uid. Fig. 3 is an enlarged bottom elevation of the bit, being a view taken as indicated by line 3-3 on Fig. 1. Fig. 4 is a view similar to Fig. 1 showing a form .of the invention employing three cutters. Fig. 5 is a bottom end elevation of the bit shown in Fig. 4, being a view taken as indicated by line 5-5' on Fig. 4, and Figures 6 and 'i' are diagrammatic views illustrating the action of' the bit provided by my invention.

The bit provided' by this invention includes, generally, a body l0 and a plurality of individually rotatable cutters 1l projecting downwardly from the lower end oi the body to be rotatable about axes parallel with-the longitudinal axis of the body. The invention contemplates the provision of a plurality of cutters in connection with the body; for instance, it' may be carried out with two or more cutters. In Figures l, 2 and 3 of the drawings I have illustrated the invention carried out with twocutters, whereas in Figures 4 and 5 of the drawings I have illustrated the manner in which the invention may be carried out with more than two cutters.

'Ihe body 10 is primarily a holder or mounting for the cutters l1 and is therefore subject to considerable modification or variation without departing from the spirit of the invention. In the particular case shown, reference now being had to Figures 1 to 3 of the drawings, inclusive, the body includes a stem or shank portion 12, and an enlarged or laterally projecting lower end portion 13. Thelstem or shank portion 12 of the body is provided at its upper end with means for connecting the bit with a string of drill pipe, or the like. In the case illustrated the shank is provided with an upwardly extending tapered screw threaded projection or pin 14 for the purposeof making this connection. The lower or enlarged end portion 13 of the body is preferably flattened in one direction and projects laterally in the opposite -direction to support the cutters 11 in the desired position with reference to the central axis of the tool, the portion 13 is preferably made as thin as possible between the cutters. In the preferred construction the lower end of the body portion 13 is finished so that it is in the form of a at face 16 lying in a horizontal plane. It is to be understood, of course, that the body is proportioned to form the necessary support or carrier for the cutters ll at the same time occupying as little of the well bore as possible so that the circulating fluid discharged at the bit is allowed to circulate freely upward around the bit.

In accordance with the invention, the cutters 1l are symmetrically disposed with reference to the central axis of the bit, that is, in the case of a bit having two cutters they are located diametrically opposite each other, while in the case of a bit having three cutters they are located 120 degrees apart around the central axis of the bit. By -symmetrically arranging the cutters about the central axis of the bit, the structure is balanced so that it operates smoothly and drills straight into the formation.

The cutters are proportioned, that is, made of such diameter with reference to the size of the body, and are so located on the bottom end of the vbody as to project laterally beyond the margins of the body and at the same time more or less closely approach the central axis of the body. The cutters are related, however, so that there is clearance between them thus eliminating danger of the cutters fouling each other or the danger of a small object, such es a piece of the formation, getting between the cutters in a manner to foul them.

In accordance with the invention the cutters to the body in various manners so that they have' the desired action with reference to the body.

In the preferred form of the invention each cutter 1l vis mounted on a. spindle or stud 20 which projects downwardly from the face 16 of the body 10. In the particular case illustrated each cutter carrying stud is detachably connected with the body, being screw threaded into a socket 21 formed upwardly in the body portion 13 from the end face 16. The stud ts tightly in the socket 21 fand may be provided with a shoulder 22 to seat against the end face 16 in the manner clearly illustrated in Fig. 2 of the drawings.

Each cutter 11 is cylindrical in its generalco'nattacca figuration, the cylinder beins tiet at its ends; the upper end for communication of vertical thrust to the body. and the lower end forenggement with the bottom of the bore. The cutter is. how-'- ever, not a solid or continuous cylindrical Structure but is formed o! e. plurality of teeth 2c which are-preferably spaced e substantial distance eport circumerentially to give circulation clearance and to obtain the underresrning effect which will be apparent from the diagrams Figures t and 7.

The teeth are joined together or formed on a central hub 26 which is rotatably supported on i the spindle 2t. In the particular case shown the hub 2o has a central longitudinal bore 37 extending: through it from one end to the other, which bore receives the spindle 2li. in practice hub ier instance, where the core 2li extends through hub the spindle may pro ntiy beyond the lower end of the hun wl" re .it tney be provided with a ludici throne 2t to overhang the lower end ci the hub in the manner clearly illustrated in Fig. 2 ci the drewings. The upper end ci" the cutter, for instance, the upper end of the hub 2t is tiet and adapted to communicate vertical thrust to the body. in the cese shown thrust washers 30 andl ol suitable material are interposed between the upper end of the cutter and the face 16 of the body to taire the weer between thecutter and body.

The thrust washer 3d engages the face it oi the body and is heid against rotation relative to the body by a pin '32, while the thrust washer 31 engages the upper end of the cutter and is heid against rotation relative to the cutter by e pin 33. When employing the form ci mounting for the stud shown in the drawings, the stud may be provided at its lower end with a head part 3a adapted to be engaged by a wrench. or the like, to facilitate scrcwiruz,r the stud into and from the socket 2i. The teeth. 25 of the cutter are an important phase of the present invention and in their preferred form they have horizontally disposed lower end cutting edges 36 and perpendicular or vertically disposed side cutting edges 3'?. The end cutting edges 36 extend inwardly from .the periphery of the cutter. In a case where the cutter The side or outer is mounted by a stud passing upwardly through it from its lower end. the edges 3o terminate before reaching the centeroi' the cutter. as will be apparent from the drawings. The pitch or anguinrity oi the edges 30 across the end oriace of the cutter may vary. In the illustrated the edges 36 are arranged to extend redially with reference tothe axis oi rotation ci the cutter. The teeth are provided on, for instance formed integral with the hub 26. and preferably entend or project a substantiel distance downwardly below the hub es illustrated throughout the drawings. The teeth 25 protect outward 'seyond thehub 28 and preferably extend longitudlnailyot the cutter from one end to the other. if oi the teeth my be llnished or dressed to present cutt eo '37 adapted to sot on the side wall oi the as the tool operates. By thus extenclius the teeth 25 vertically the entire length or the cutter, the

. l bit is provided with ample side cutting parts to maintain the hole to scuse, It is to be under@ stood, ci course. that the teeth, for instance, the

best advantece and 'that the parte maybesuit-t secured on the spindle in any sultatile.

may be attached.` The circulation opening 40 preferably extends vertically through thel body from one end to the other, and at the. lower end of the body it is preferably restricted or reduced, f

as by a reducer 4.5, so that the circulating fluid jets downwardly at the center or the bit at a high velocity. The circulating iiuid thus dischareewill, after leaving the body, pass ra diaiiy outward around and through the cutters in a manner to efiectively ilus-h them to lieep them in opere-tion condition. Further, in accordance with the preferred form ci the invention proviu sion may be rior discharging circulating' fluid at the ind ual cutters. inthe form of the lnycntion sho ori brunch circulation openings Aiii are provider.. .n body to introduce circulating fluid into contrai circulation passages i7 iol-ined through the studs 2o.. in the studs discharge downwardly at the lower ends oi the studs. Circulating fluid discharged from the studs 47 circulates out between the downwardly projecting teeth-iikeparts below the studs, thus keeping them flushed clean and in proper operating condition. By making the several discharge openings the same size, the discharge from them will be substantially equal.

it will be obvious that the principles oi the invention are present in both of the forms illustratecl in the drawings, that is, in the bit employing two cutters es shown in Figures l, 2 and 3 as well as in the bit employing three cutters as shown in Figures i and 5. 'ifne general mode oi operation of either form oi the invention is the same, and. in fact, the general construction of the two i'orms oi' the general invention is the same. In the caseV of a three-way or three-cutter bit, as shown in Figures fi and 5, the body part 13, instead of being flattened to project laterally in diemetrically opposite directions, is made to project in three different directions equally spaced around the airis of the bit as will be apparent from the drawings.

By properly relating and proportioning the q ports oi the tool, the desired undercutting or undcrreaming action may be obtained. The underlreexnii'ig action of the bit will be best understood from consideration of the diagrams Figuros 6 and '1. in Fig. 6 the cutters indicated diagremi'naticaily at A are rotatably positioned so that therbit will pass throuah a casing or opening: having internal diameter corresponding to the circle E. in Fig. 'lv l illustrate by the circles C the cuts made by the individual rotation of the cutters, and I indicate by the circle D the out made by the entire bit. it will be apparent that the bit when in operation cuts a larger hole or bore than is required to pass it. The independn ence ci the individual `cutters allows them to assume the positioiiiinsg` shown in Fic. c so that the tool can be raised and lowered through an open- 1 ing the size of the circle E. In practice it is deu sidablc to bevel the upper end of the laterally prolectin@ portions ci the cutters as at lo to facilitate withdrawal oi e bit, for instance, the drawing of the bit uordly into a casing which may have 'en internal diameter such as is represented by the circle'B in Fig. t.

lai

In operation the bit applied to the lower end of a string of drill pipe is lowered into the well bore and as the bit is rotated by the drill pipe, it is lowered into engagement with the bottom of the bore. The engagement of the bit with the formation, for instance, with the bottom of the bore and the side walls of the bore, causes the cutters to rotate individually about their axes as the bit rotates bodily. The bodilyv rotation in' 'r the general direction of rotation of the bit represented by the arrow X inA Fig. 7 is opposite to that of the individual rotation of the cutters as indicated by the Tarrows Y in Fig. 7. It will be apparent that the individual cutters will turn on their axes faster than the bit turns\about its axis, thus gaining an effective speed of engagement of the cutting parts with the'forrnation without rotating the drill pipe or the bit rapidly. As the'bit is lowered against the formation, the edges 36 of the cutters have a combination twisting. grinding, and scraping action on the formation which effectively cuts it away. The parts of the cutters may be so spaced and proportioned that the cuttings are effectively flushed or washed away by the circulating fluid, leaving the bit free for efficient operation. The vertical thrust coming upon the cutters due to lowering the bit against the bottom of the bore, is transmitted to the body in an effective manner without tending to distort or bind the cutters.-

Having described only typical, preferred forms and applications of my invention, I do not wish to limit myself to the specific details set forth, but wish to reserve to myself any changes or variations that may appear to those skilled in the art or fall Within the scope of the following claims. f

Having described my invention, I claim:

1. A bit for use on an operating string of drill pipe including, a body having a central longitudinal uid passage, cutters, means mounting the cutters on the lower end of the body for independent rotation about vertical axes symmetri cally spaced about the central longitudinal axisv of the body including tubular spindles rotatably supporting the cutters, and longitudinal cutting parts on the cutters spaced substantial distances apart circumferentially o f the cutter's, the said central longitudinal fluid passage discharging from the lower end of the body between the cutters and the spindles being in communication with the said vpassage to discharge from the lower end of each cutter.

2. A rotary well drilling bit including, a body adapted to be rotated, a plurality of cutters, drilling blades on the cutters spaced substantial distances apart circumferentially of the cutters and being in planes radial relative to the cutters, and means mounting the cutters on the lower end of the body to rotate free of one another about axes parallel with and spaced from the axis of rotation of the body, the cutters being proportioned and positioned with respect to the body so that the said blades project beyond the periphery of the body during operation of the bit to make a bore of greater diameter than the body and so that the cutters may be positioned whereall of the said blades are within a circle of substantially the same diameter as the body whereby the bit may be passed through an opening of less diameter than said bore.

3. A rotary well drilling bit including, a body adapted to be rotated, a plurality of cutters, drilling blades on the cutters spaced substantial distances apart circumferentially of the cutters and being in planes radial relative to the cutters, cutting teeth projecting downward from the lower end of the cutters, and means mounting the cutters on the lower end of the body to rotate free of one another about axes parallel with and spaced from the axis of rotation of the body. the cutters being proportioned and positioned with respect to the body so that the said blades project beyond the periphery of the body during operation of the bit to make a bore of greater diameter than the body and so that the cutters may be positioned where all of the said blades are within a circle of substantially the same diameter as the body whereby the bit may be passed through an opening of less diameter than said bore.

4'. A rotary well drilling bit including, a body adapted to be rotated, a plurality of cutters, drilling blades on the cutters spaced substantial distances apart circumferentially of the cutters and being in planes radial relative to the cutters, and means mounting the cutters on the lower end of the body to rotate free of one another about axes parallel with and spaced from the axis of rotation of the body, the cutters being proportioned and positioned with respect to the body, so that the said blades project beyond the periphery of the body during operation of the bit to make a bore of greater diameter than the body and so that the cutters may be positioned where all of the said blades are within a circle of substantially the same diameter as the body whereby the bit may be-passed through an opening of less diameter than said bore, the said means including tubular studs rotatably carrying the cutters, the studs being 4in communication with a circulation opening in the body.

5. A rotary well 1drilling bit including, a body adapted to be rotated, a plurality of cutters, projecting cutting parts on the cutters spaced a substantial distance apart circumferentially of the cutters, and means rotatably mounting the cutters on the bottom of the body to project downwardly therefrom and in positions where the cutting parts may project beyond the periphery of the body to drill a bore of greater diameter than the body, the cutters being independently rotatable whereby they can be turned to positions where the cutting parts are all within a circle of the same or less diameter than the body so that the bit can be passed through an opening of less diameter than that of the bore made by the bit.

6. A rotary drilling bit including, a body adapted to be rotated, a plurality of cutters each having a plurality of substantially radially projectingblades spaced substantial distances apart circumferentially of the cutter, and means mounting the cutters on the body to project downwardly therefrom and to be independently rotatable about axes spaced from and substantially parallel with the axis of rotation of the body, the cutters being proportioned and positioned relative to the body so that the bit can be passed through an opening smaller in diameter than the bore made when the cutters rotate about their axes when the body rotates about its axis.

7. A rotary drilling bit including, a body adapted to be rotated, a plurality of cutterseach having a plurality of blades projecting substantially radially of the 'cutter and spaced substantial distances apart circumferentially of the cutter, and

the body, the cutters being proportioned and posi- L tioned relative to the body so that the bit can be passed through an opening smaller in diameter than the bore made when the cutters rotate about their axes when vthe body rotates about its axis, the blades of each cutter having straight side cutting edges parallel with the axis oi rotation of the cutter. l

8. A rotary drilling bit including, a body adapted to be rotated, a plurality of cutters each having a plurality of blades projecting substantially radially of the cutter and spaced substantial distances apart circumferentially of the cutter and means mounting the cutters/on the body to project downwardly therefrom and to be independently rotatable about axes spaced from and sub stantially parallel with the axis or rotation of the body, the cutters being proportioned and positioned relative to the body so that each cutter cuts from a point close to the axis oi.' rotation of the body to a point outward or" the outermost part of the body and so that the bit can be passed through an opening smaller in diameter than the bore made when the cutters rotate about their axes when the body rotates about its axis.

9. A rotary drilling bit including, a body adapted to be rotated and having a at lower end at right angles to its axis of rotation; a plurality of cutters each having aplurality ot blades projecting substantially radially o! the cutter and spaced substantial distances apart circumferentially of the cutter, and means I,mounting the cutters on the fiat lower end or the body to project downwardly therefrom and to be independently rotatable about axes spaced from and substantially parallel with the axis of rotation of the body, the cutters being proportioned and positioned relative to the body so that the bit can be passed through an opening smaller in diameter than the bore made when the cutters rotate about their axes when the body rotates about its axis.

10. A rotary drilling bit comprising a body, a plurality oi cutters `rotatably mounted upon the body for rotation about substantially vvertical axes, each of the several cutters having more than two radially extending blades and being adapted during rotation to rotate independently of adjacent cutters about an asis which is spaced from the axis of rotation ci the body, the out ting edges of eh blade being horizontally ar ranged, arid the cutters being arranged near the sides or the bit so that during rotation their blades may string through arcs which project materially beyond the sides ci. the bit. A

l SAMUEL RAY HOPmS.

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